‘It’s thought that 4 per cent of the global population is plagued by a persistent, rumbling sound in their ears – the source of which is a total enigma. Ellie Harrison speaks to the people who’ve been trying to get to the bottom of a noise that has been wreaking havoc for many years…

The earliest reliable reports of the Hum date from the Seventies, when numerous Bristol residents wrote letters to the Bristol Evening Post to complain about hearing the noise, which has since been compared to the sound of an idling truck or thunder – and is different from tinnitus. Some Bristolians still hear it to this day, and it’s been reported in places around the world, from the suburbs of Tokyo to Taos in New Mexico and Largs in Scotland. It’s left many “hearers” anxious and depressed, and has been linked to several suicides. Over the years, many theories have been posed and investigations conducted, but there is no clear consensus on the cause…’ ( Ellie Harrison via The Independent )